The apparatus of this invention is a wind driven heating system which efficiently converts the kinetic energy of wind into heat for a wide range of wind velocities.
It has long been recognized that wind energy is a potentially important source of usable energy, and attempts have been made to provide wind driven heating systems suitable for heating homes, buildings, greenhouses, and other structures. One example of such an attempt is the system described by Ashikian in U.S. Pat. No. 3,752,395. Ashikian's heating system includes a wind powered turbine which is used to power a centrifugal pump which forces a fluid through a small diameter pipe. Ashikian states that the shear stresses created by this fluid flow cause a portion of the kinetic energy of the flowing fluid to be dissipated as heat which is stored for use.
While systems such as that described by Ashikian do serve to convert a part of the available wind energy into heat, they suffer from certain disadvantages. First, these systems do not efficiently extract energy from the wind for a wide range of wind speeds. In order for an energy conversion system such as a wind driven heating system to operate efficiently, the energy converter should consume a large percentage of the available energy supplied by the turbine for a wide range of turbine speeds. That is, for any given turbine speed, the energy converter should convert a large percentage of the available mechanical energy of rotation of the turbine into heat. In practical terms, this means that it is desirable to have the energy converter consume energy at the same ratio to the turbine speed as the available wind energy. The Ashikian system extracts energy from the wind turbine with a centrifugal pump which forces a fluid through a small diameter pipe. Such a system does not consume energy at the same ratio to the turbine speed as the available wind energy, and, therefore, the Ashikian system cannot function efficiently for a wide range of wind velocities.
Second, Ashikian teaches the use of a long, small diameter pipe to convert the kinetic energy of fluid pumped by the centrifugal pump into heat. In some applications, the cost and bulk of this pipe may limit the applications in which the heating system may advantageously be used.
It is the primary object of the present invention to overcome these and other disadvantages of wind driven heating systems in the prior art.